Define SOL_TCP and SOL_UDP for WASIp1

[Hokila]

Summary

• define SOL_TCP and SOL_UDP for the WASIp1 <sys/socket.h> path
• add compile-time assertions for the socket-level values
• register the regression test across supported WASI targets

Fixes #855.

Testing

• verified the new WASIp1 assertion test fails before the header change because both constants are undeclared
• verified the same WASIp1 syntax-only compilation succeeds after the header change
• git diff --check

Environment limitations

• cargo test --manifest-path tools/wasi-headers/Cargo.toml reaches the existing assert_same_as_src test but fails because the checked-in wasi/api.h already differs from the generator output
• the full local CMake target is blocked by Apple ar rejecting the project's empty archive command
• WASIp2/WASIp3 CMake configuration requires Clang 22+, while this host provides Apple Clang 21; their source branch is unchanged by this patch

[alexcrichton]

Personally I feel that given the state of networking on the wasip1 target, which is mostly broken, I am not confident myself in landing changes like this. I think it would be best to leave the wasip1 target as-is and focus on fixing/improving the targets with actual support for networking in wasip2/wasip3.

Do you have a specific motivation though for proposing this change?

[Hokila]

Thanks, that makes sense. I don't currently have a concrete WASIp1 networking use case beyond fixing the inconsistency between predefined-macros.txt and <sys/socket.h>. Since this does not improve runtime networking support, I agree that it may not be worth extending the WASIp1 surface.

I’m happy to close this PR and focus on WASIp2/WASIp3 instead.